kernel trap 12 with interrupts disabled

[Markus Trippelsdorf]

Just got this panic on my amd64 smp system running stable:

kernel trap 12 with interrupts disabled

Fatal trap 12: page fault while in kernel mode
cpuid = 0; apic id = 00
fault virtual address   = 0x20
fault code              = supervisor read, page not present
instruction pointer     = 0x8:0xffffffff80286611
stack pointer           = 0x10:0xffffffffb1921b70
frame pointer           = 0x10:0x4
code segment            = base 0x0, limit 0xfffff, type 0x1b
                        = DPL 0, pres 1, long 1, def32 0, gran 1
processor eflags        = resume, IOPL = 0
current process         = 14 (swi4: clock)
trap number             = 12
panic: page fault
cpuid = 0

(kgdb) list *0xffffffff80286611
0xffffffff80286611 is in softclock (/usr/src/sys/kern/kern_timeout.c:220).
215                     curticks = softticks;
216                     bucket = &callwheel[curticks & callwheelmask];
217                     c = TAILQ_FIRST(bucket);
218                     while (c) {
219                             depth++;
220                             if (c->c_time != curticks) {
221                                     c = TAILQ_NEXT(c, c_links.tqe);
222                                     ++steps;
223                                     if (steps >= MAX_SOFTCLOCK_STEPS) {
224                                             nextsoftcheck = c;

(kgdb) backtrace
#0  doadump () at pcpu.h:172
#1  0x0000000000000037 in ?? ()
#2  0xffffffff80276e97 in boot (howto=260) at /usr/src/sys/kern/kern_shutdown.c:409
#3  0xffffffff80277611 in panic (fmt=0xffffff007ba5ebe0 "\200\026\221{") at /usr/src/sys/kern/kern_shutdown.c:565
#4  0xffffffff80390e5f in trap_fatal (frame=0xffffff007ba5ebe0, eva=18446742976271029888)
    at /usr/src/sys/amd64/amd64/trap.c:660
#5  0xffffffff80391386 in trap (frame=
      {tf_rdi = -2141705632, tf_rsi = 10548215, tf_rdx = 16, tf_rcx = -1619509088, tf_r8 = -1097437156384, tf_r9 = -1619509256, tf_rax = 1, tf_rbx = 1, tf_rbp = 4, tf_r10 = 30689, tf_r11 = -1097437156384, tf_r12 = 16, tf_r13 = 4, tf_r14 = 0, tf_r15 = -2144279856, tf_trapno = 12, tf_addr = 32, tf_flags = 0, tf_err = 0, tf_rip = -2144836079, tf_cs = 8, tf_rflags = 65542, tf_rsp = -1315824768, tf_ss = 16}) at /usr/src/sys/amd64/amd64/trap.c:238
#6  0xffffffff8037cd6b in calltrap () at /usr/src/sys/amd64/amd64/exception.S:168
#7  0xffffffff80286611 in softclock (dummy=0xffffffff80582a60) at /usr/src/sys/kern/kern_timeout.c:220
#8  0xffffffff8025d959 in ithread_loop (arg=0xffffff0000048680) at /usr/src/sys/kern/kern_intr.c:682
#9  0xffffffff8025c0f7 in fork_exit (callout=0xffffffff8025d810 <ithread_loop>, arg=0xffffff0000048680,
    frame=0xffffffffb1921c50) at /usr/src/sys/kern/kern_fork.c:805
#10 0xffffffff8037d0ce in fork_trampoline () at /usr/src/sys/amd64/amd64/exception.S:394
#11 0x0000000000000000 in ?? ()

Any hints?
-- 
Markus